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From "Martin Ritchie (JIRA)" <qpid-...@incubator.apache.org>
Subject [jira] Updated: (QPID-1432) Client can fail to notify all stateWaiters
Date Wed, 05 Nov 2008 12:27:44 GMT

     [ https://issues.apache.org/jira/browse/QPID-1432?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Martin Ritchie updated QPID-1432:
---------------------------------

    Description: 
Summary:

Due to our desire to reduce synchronization on the client it is possible to fail to notify
a client of an exception state.
As highlighted by the two thread processes below, the _waiters in AMQStateManger can be updated
such that the error notification fails to take place.


This is due to our use of CopyOnWrite lists. As the Exception handler is propagating the exception
a new exception may miss a newly registered state listener.

Suggested change:

All uses of the _waiters should be synchronized. The only place that this is not done is in
the error() case.

  was:
Summary:

Due to our desire to reduce synchronization on the client it is possible to fail to notify
a client of an exception state.
As highlighted by the two thread processes below, the _frameListeners can be updated such
that the notification fails to take place.


This is due to our use of CopyOnWrite lists. As the Exception handler is propagating the exception
a new syncWait can occur, which will fail as the connection is closed. There is a question
of why the socket write does not fail but that may be because the close has not yet occurred.

Suggested change:

All uses of the _frameListeners should be synchronized and the syncWrite should check to see
if the connection is closed before allowing the adding the listener. Throwing any exception
that has already been set.


> Client can fail to notify all stateWaiters
> ------------------------------------------
>
>                 Key: QPID-1432
>                 URL: https://issues.apache.org/jira/browse/QPID-1432
>             Project: Qpid
>          Issue Type: Bug
>          Components: Java Client
>    Affects Versions: M2.1, M3
>            Reporter: Martin Ritchie
>            Assignee: Martin Ritchie
>            Priority: Critical
>             Fix For: M4
>
>
> Summary:
> Due to our desire to reduce synchronization on the client it is possible to fail to notify
a client of an exception state.
> As highlighted by the two thread processes below, the _waiters in AMQStateManger can
be updated such that the error notification fails to take place.
> This is due to our use of CopyOnWrite lists. As the Exception handler is propagating
the exception a new exception may miss a newly registered state listener.
> Suggested change:
> All uses of the _waiters should be synchronized. The only place that this is not done
is in the error() case.

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